Measurement of the action of a single nerve of a freely moving animal is important for elucidation of brain functions. However, such measurement cannot be easily performed and efforts to do so have been ineffective.
A microelectrode that has been conventionally used for measuring nerve action potentialsaction potentialsneurons is produced by coating the outer circumference of a metal wire having a thickness ranging from about 20 μm to 80 μm with insulation paint and then cutting the metal wire with scissors or the like to expose the end parts. In general, a plurality of such microelectrodes are bundled and then used as a multi-channel electrode. When conventional microelectrodes are multi-channeled and then measurement is performed in neural population, the proportion of microelectrodes capable of recording nerve action is low (e.g., only 1 to 3 out of 8 microelectrodes can recordnerve action). Also, the waveform amplitude of action potentials recorded is small, which is about several times greater than the amplitude of the background noise (100-200 microvolts).
Patent document 1 and non-patent document 1 are presented as patent documents relating to the present invention.                Patent document 1 JP Patent Publication (Kokai) 2006-212133 A        Non-patent document 1 Umeda et. al, Electrochimica Acta, 48 (2003) 1367-1374        